This invention relates generally to an electrostatic printer, and in particular, to an electrostatic printer which prints latent images on an electrostatic recording paper, which paper can be developed to allow the images formed to become visible.
The substantial reduction in cost of word processors, computers and the like has allowed many more consumers to purchase and operate such systems. Thus, the average consumer now has the financial means for purchasing a computer or word processing system, and with the reduction in complexity of such systems, can readily learn how to operate such a system. Before this advance, only experts in electronic data processing systems or similar systems had the specific technical knowledge required to operate such a computer system. The substantial cost reduction of such systems was due to the cost reduction of the system's component parts such as the central processing unit (CPU), memory and the like which resulted from the technological advances in semiconductor manufacturing. However, the technology of the printer portion of computers or word processing system has not kept pace with the rapidly expanding technology utilized in connection with other components of such systems.
The conventional electrostatic printer utilizable in connection with a computer system is generally driven only at low speeds. In order to provide high speed printing, an electrostatic printer which is complicated in structure, over sized and expensive, is necessary. Accordingly, the conventional high speed electrostatic printer could only be utilized for specialized purposes such as in the output terminal or line printer of a general-purpose computer.
The lack of advanced technology in electrostatic printers presents problems particularly recognized for word processors for Chinese characters. The word processor for Chinese characters which was previously unavailable, has become inexpensive enough to be brought into wide use. A user of a word processor for Chinese characters would prefer the printed output to be a mixed writing of Chinese characters with Japanese syllabary as opposed to Roman letters or square Japanese syllabary.
In the conventional electrostatic printer, the Chinese characters cannot be printed out at all since the resolution of such conventional printers is insufficient, although conventional electrostatic printers are generally sufficient to print out alpanumerical characters. Thus, a conventional electrostatic printer having a resolution of 5.times.7 dots or 9.times.11 dots is sufficient to print out alphanumerical characters but is insufficient to print Chinese characters. A resolution of about 32.times.32 dots is required to visibly print out Chinese characters.
In order to solve the resolution problem discussed above, the printing speed of the conventional electrostatic printer had to be substantially reduced. However, in a computer or word processing system, a high speed printer is desired and accordingly the printer becomes very expensive. The only printers that can meet the above requirements are optical type printers in which lasers or optical fiber tubes (OFT) are utilized, or electrostatic printers with a multi-stylus. Since both of these types of printers are very expensive, the cost of a complete system is increased thereby preventing the widespread acceptance and use of such computer or word processing systems. The above is true also in high speed facsimile or cathode ray tube (CRT) hard copiers. Accordingly, an electrostatic printer that is reliable, is inexpensive to manufacture and which provides good resolution and printing quality, is desired.